Pressure and thermal material forming device



March 5, 1963 v. K. KENNEDY PRESSURE AND THERMAL MATERIAL FORMING DEVICE 2 Sheets-Sheet 1 Filed Aug. 2, 1955 5 a a z a INVENTOR. VERNAL KENNETH KENNEDY BY March 5, 1963 v. K. KENNEDY PRESSURE AND THERMAL MATERIAL FORMING DEVICE 2 Sheets-Shee t 2 Filed Aug. 2, 1955 EN TOR.

IN V VERNAL KENNETH KENNEDY IIIIII/I/I Aaent United States Patent 3,080,473 PRESSURE AND THERMAL MATERIAL FORMING DEVICE Vernal K. Kennedy, "an Nuys, Califi, assignor to Lockheed Aircraft Corporation, Burbank, Calif. Filed Aug. 2, 1955, Ser. No. 525,838 8 Claims. (Cl. 219-449) This invention relates to thermal forming devices and more particularly to an improved thermal forming device which relies on the thermal condition of the material being formed to control the forming operation.

In the held of sheet metal forming, and other similar applications such as the heading of rivets, rigid material often is formed by heating the material to a condition where it becomes pliable followed by the application of a strong force or pressure which forms the material into a desired shape. For example, in conventional dimple forming machines, forming tools are employed having afiixed thereto several heating elements. Upon engagement of the tools with the material, heat generated by the elements is transferred to the material by means of the tools for a predetermined period of time. This period of time is generally known as the time setting or dwell period, and is determined in part by the area being heated and the type of material used. Usually at the end of a dwell period, a timer switch is employed to cause a strong force or pressure to be applied to the forming tools which causes the material to assume the shape of the forming tools. If additional dimples are to be formed, the dwell period remains constant for each dimple formed, regardless of the material temperature.

A difliculty exists in such a conventional thermal forming device due in part to the fact that the strong force is sometimes applied before the material has been adequately heated. Forming in this manner causes the shaped material to be brittle, which results in cracking and eventual breakdown of the material. Furthermore, the forming operation is slow and ineflicient due to the lack of positive control of the forming tools during the operation. This generally results in a loss of material strength due to overheating.

These difficulties are overcome in the present invention in which I provide heating elements aifixed to a forming tool having the configuration of the shape desired in the material. Heat generated by the elements is transmitted to the material in order to make it pliable. A low pneumatic pressure means is employed for initiating movement of the forming tool which commences the operation cycle. A trigger mechanism, following the movement of [the forming tool, operates a valve switch means which connects a high pneumatic pressure means to augment the applied low pressure thus further activating the forming tool. The additional pressure forces the forming tool to complete the forming operation. It is to be understood that the pressure system employed may take a form other than pneumatic such as for example a steam or hydraulic fluid system.

The action of the trigger mechanism and therefore the activation of the valve switch means is dependent upon the material temperature during the initial cycle of operation since as the material becomes more pliable, the forming tool is pressed further against the material. If the material has not been properly thermally conditioned, the rigidity of the material will prevent the activation of the trigger mechanism.

Thus, it can be seen that the application of high pneumatic pressure will not occur until the thermally conditioned material has become pliable.

Exhaust means are provided for disposing of the air which forced the forming tool to complete the operation 3,080,473- Patented Mar. 5, 1963 so that the forming tool may be returned to its rest position.

A feature of the present invention resides in the fact that the areas adjacent the thermally conditioned area have accumulated heat present so that additional material forming in these adjacent areas requires less dwell time than the initial forming operation. Since material forming is dependent upon a fixed dwell time for every operation, loss of strength due to overheating is negated and a series of forming operations may be accomplished having variable dwell times which is time-saving for many operations.

It is a general object of the present invention to provide a novel means for thermally conditioning material so that fiorming thereof will not occur below a minimum required temperature.

Another object of the present invention is to provide a rapid and emcient means for forming material thermally.

Still another object of the present invention is to provide a novel thermal forming means having an economical and simplified thermally operated mechanism for providing positive operation control.

A further object of the present invention is to provide novel means for controlling the application of pneumatic pressure placed on the forming tool.

An additional object of the present invention is to provide a method of forming rigid material so that the presence of a strong force will be applied only when the material has been thermally conditioned.

With the above and other objects in View, my invention consists in the arrangement, combination and details of construction disclosed in the specification and drawings, in which:

FIGURE 1 is a side elevational View of a thermal dimpling device in accordance with the present invention being shown partly in fragmentary section;

FIGURE 2 is a front elevational view taken along line 22 of FIGURE 1 showing a trigger mechanism employed in the device :of FIGURE 1;

FIGURE 3 is an enlarged front elevational view of the trigger mechanism shown in FIGURE 2;

FIGURE 4 is a schematic drawing of the device shown in FIGURE 1 FIGURE 5 is an enlarged sectional view showing the forming tools employed in the device of FIGURE 1 initially shaping material to form a dimple;

FIGURE 6 is an enlarged sectional view showing the forming tools employed in the device of FIGURE 1 having formed approximately of the dimple shape;

FIGURE 7 is an enlarged sectional view showing the forming tools shown in FIGURE 1 completing a dimple forming operation;

FIGURE 8 is a side elevational view in section showing another embodiment of the present invention for shaping rigid sheet material; and

FIGURE 9 is a side elevational view in section showing the embodiment of FIGURE 8 at the completion of the shaping operation.

Referring to FIGURE :1 and FIGURE 4, a pair of forming tool means 1d and 11 are provided for shaping a sheet of rigid material 12. The forming tool means are configured in such a manner that their co-action when activated produces a desired shape in the material.

A conventional heating means, such as electrical heating devices 13 associated with the forming tool means, are employed for thermally conditioning the material by generating heat via the forming tool means into the surrounding material area. The heating devices are electrically connected to boxes such as junction box 14 by means of a connector lead 15. An electrical source (not shown) is connected to the junction box via cable 16 which provides the required high current for generating heat to the material. 'Each junction box is provided with a start button 17 and stop button 18 for controlling the operation of the heating devices. V V

The forming tool means are attached to a base assembly 19 having an open .cut-out portion represented by the numeral 20. The forming tool means are located within the open cut-out portion so that material 12 may be passed into engagement therewith.

A tubular or cylindrical passage 21 is provided in the base assembly extending from the top thereof to the open cut-out portion. A shaft portion 22 of the forming tool means 10 passes through the cylindrical passage and is resiliently mounted therein by means of a spring 23 com pressed between a bushing 24 affixed to the base assembly and a retaining ring 25 ailixed to the shaft portion. A top bushing 26, affixed to the top portion of the cylindrioal passage co-acts with bushing 24 to guide the shaft portion perpendicularly to the material 12..

Forming tool means Ill may be moved longitudinally within the cylindrical passage to effect engagement with the material by any conventional means. A cylinder 27, having a pair of operating chambers 2d and 29' and a piston 60 within operating chamber 29, is employed in the device of FIGURE 1 which is suitable for activating the forming tool means. The operating chambers are separated by a casing wall 31 of a casing 32 which forms operating chamber 29. The piston located in operating chamber 29 is attached to an extension arm 33'ivhich passes through the casing wall into the operating chamber 28 via a sleeve 34. i 7

Operating chamber 28 is formed by an outer casing 35 which has attached thereto a flat top cam means 36. Cylindrical passage 21 extends through the base assembly to operating chamber 2% A lower cam means 37 is pivotally mounted within operating chamber 28 and is providedwith a flat cam surface 38 and an angular cam surface '39 which is engageable with the shaft portion of the forming tool means.

Aflixed to extension arm'33 within operating chamber 28 is a pair of rollers 44) and 41 arranged to ride on the top cam means and the flat cam surface, respectively. Piston movement is rectilinear on the flat top cam means 36. Progression of piston forces the lower cam means to pivot. Inasmuch as angular cam surface 3% is in engagement with the shaft portion, any pivotal move ment of lower cam means 37 positions the shaft portion longitudinally in the cylindrical passage and thereby positions forming tool means 10 in a perpendicular relationship to the material.

Piston movement is effected by employing a pressure system such as a pneumatic pressure system for example. High pneumatic pressure is provided from any suitable source (not shown) through a system-network represented by an arrow 42.

The pneumatic system comprises a low pneumatic pressure regulator means 43 having a gage 44; for indicating the pneumatic pressure applied to the subsequent systeml A check valve 45 is coupled to the low pneumatic pressuremeans through which the low pressure passes. The

check valve servesto maintain the pneumatic pressure flow with" as little fluctuation as possible. A low pressure valve 46 is connected tothe check valve via a. pneumatic'reservoir 47. The low pressure valve is electrically operated by means of a solenoid d3. The solenoid is connected to ground via lead 49 and connected to a positive source of potential (not shown) via a switch 50, a foot pedal switch means 51, and a lead 52.

A rod 53,"composed of maghetizable material, is ar ranged to form a movable core within the solenoid 4d so that when the solenoid is energized the rod will move.

Attached to the rod on one end is a pivotal extension 54 which; is attached to the low pressure valve yandmovs I able therewith.

The, low pressure, valve is provided with passage 55 ex tending therethrough and forming a right angle within the center of the low pressure valve.

The piston 3a is activated by energizing solenoid 48 which arranges passage 55 so that pneumatic pressure is pneumatic pressure source 42 and the low pressure valve 46 and is constructed similarly thereto. The high pressure valve is operated by a solenoid 59 which when energized applies high pneumatic pressure directly to the low pressure valve to advance the piston. De-energizing of solenoid 59 causes the high pressure valve to disconnect the high pressure from the piston cylinder.

A probe so is provided on the end of the'extension arm which passes through the outer casing at the end of a piston stroke. The probe is employed for tripping switch 5% which in turn breaks electrical contact to solenoid 43 and causes its de-energization. 7 v7 A trigger mechanism, represented by the numeral 62, is mounted on the front. of the base assembly adjacent the shaft portion and is shown more clearly in FIGURE 2 and FIGURE 3. The trigger mechanism i-s employed for controlling the operation of solenoid 59 and comprises a plunger 63 slidably mounted in a groove 64 and engageable with a set screw 65. 7

One end of the lower cam means extends beyond the 7 Outer casing to engage plunger 63. The plunger is moved longitudinally in groove 64 by the pivotal action of the lower cam means. In this manner, the movement of the plunger follows the movement of forming tool means It).

A bellcrank 66, affixed to set screw as, pivots when the set screw is engaged by the plunger so that its movement is transferred via a push-rod 67 toactivate a switch 68 which controls the high pressure valve solenoid. A spring 6% is provided for returning the bellcranlt and the plunger to their initial positions. An adjustable microm- V eter 70' mounted on the base assembly is employed for manually controlling the tripped, prior to operation.

In FIGURES 5-7, a dimpleforming tool means is shown for forming a dimple in she'et material during three stages of operation. FIGURE 5 shows the initial engagement of forming tool means 1d and 11 with the material llil when activated by the low pneumatic pressure means The continued application of low pressure to the forming tool has effected approximately 85 of the dimple.

7 It should be noted that the partially formed dimple has been accomplished only'as the material becomes more and more pliable and that noportion of the material has been formedwhich has not been thermally prepared.

7 FIGURE 7 shows a completed dimple formed in the vmaterial as .a result of applying high pneumatic pressure when the material has been properly conditioned. Since the application of high pressure occurs when the material is' thoroughly conditioned to be worked, the completed a form isnotsusceptiblef to cracking due to brittleness asa result of using conventional methods and apparatus The embodiment of the present invention, 'as shown in FIGURES 8 and 9, shows a pair of forming tool means 4 and 5 onfigu e o pr duce a I ht-aQs dfoId, or

point at which the switch is bend in rigid sheet material 76. Heating elements, such as element 77, are embedded in the forming tool near the surface of material engagement. A face plate 78 aflixed to forming tool means 75 is made of a hard material, and is employed as a form to provide a fold in the material being formed when forming tool means 74 is activated.

Forming tool means 74 is activated by applying pressure to a piston 79 within a cylinder 80. Activation of the forming tool means 74 compresses a spring 81 located within a chamber '82 formed by the forming tool means 74. This arrangement allows an extension 33 to engage the material to be formed and to bend this material against the hard face plate 7%. Heating elements 77, such as those embedded in the forming tool, are carried by the extension so that the material is thermally conditioned at all times during the forming operation.

In this embodiment of the present invention a plunger 84 is resiliently mounted on the forming tool means 74 by means of a spring 85 and a mounting bar 86. Threads 67 are provided on one end of the plunger to receive a nut 88 and spacer 89' so that the plunger 84 may slide longitudinally through a hole (not shown) in the mounting bar.

The bellcrank and switch arrangement as described in the device of FIGURE 1 is used in the embodiment of FIGURES 8 and 9 to cause the high pressure valve solenoid to energize and is represented by the numeral 91.

The pneumatic pressure system as described in the device of FIGURE 1 is used in the embodiment of FIG- URES 8 and 9 and therefore is not repeated in the drawmgs.

Actual operation will be described with reference to FIGURE 4 in which the depression of foot pedal 51 completes an electrical circuit via switch 50 to energize solenoid 48. Energizing this solenoid draws rod 53: into its core (not shown) causing low pressure valve 46 to arrange passage 55 so that low pneumatic pressure flowing through low pneumatic pressure regulator means 43 is applied to cylinder 27. As pneumatic pressure is applied to chamber 29, piston 30 is forced to move within the cylinder. Roller 41 connected to extension arm 33 follows this movement by riding on flat cam surface 38. This action causes cam means 37 to pivot. Inasmuch as shaft portion 22 rides against angular cam surface 39, the shaft portion is forced downward against the tension of spring 23. This action engages forming tool means with the material (not shown).

Heat generated by the heating elements 13, shown in FIGURE 1, embedded in the forming tool means is transmitted to the material 12. As the rigid material becomes more pliable due to this heating, the forming tool means is lowered still further since the low pneumatic pressure is still being applied. Plunger '63 following the movement of the forming tool means, eventually engages set screw 65 attached to bellcrank 66. As the plunger moves down, the bcllcrank pivots and acts against spring 69. Push-rod 67, carried by the bellcrank, engages switch 68 which closes an electrical circuit. The closing of switch 68 applies positive potential to solenoid 59. Energizing solenoid 59 causes high pressure valve 58 to arrange its passage 92 to permit the application of high pneumatic pressure to piston 3% via low pressure valve 46.

The application of high pneumatic pressure forces the piston to complete its stroke within the cylinder and complete the forming operation. The completion of piston stroke causes probe 60 to open switch 50 which causes solenoid 48 to de-energize. This action causes passage 55 to connect cylinder 27 with exhaust outlet 57. The accumulated pneumatic pressure within cylinder 27 may escape and thereby allow the piston to return to its initial position. Piston 30 returns to its initial position by reason of spring 23 forcing plunger 22 upward and hence cam means 37 is pivoted clockwise so that rollers 41 travel toward the right to reposition the piston. Spring 23 which forces plunger 22 upward was placed under compressive force during the travel of the piston 30 toward the left as shown in FIGURE 4. It is this stored mechanical energy which quickly repositions the piston for the next forming operation.

Sufficient pneumatic pressure is retained in the pneumatic system and reservoir 47 to permit efficient reactivation of piston movement upon another depression of the foot pedal.

The pneumatic pressure system employed in FIGURE 1 may be used to activate forming tool means '74. Operation of the bellcrank and switch arrangement 91 is the same as for the device shown in FIGURE 1.

Having described only typical forms of the invention I do riot wish to be limited to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art and fall within the scope of the following claims.

I claim:

1. A forming device for shaping a material having a certain yield point at which the material becomes fully pliable comprising, the combination of a base assembly, a forming tool movable on the base assembly, means carried on the base assembly for supporting the material and for cooperating with the tool in shaping the material, heating elements aflixed to the forming tool in thermal relationship to the material for making the material pliable, activating means carried by the base assembly for moving the forming tool, a fluid pressure system connected to the activating means comprising a low fluid pressure valve and a high fluid pressure valve, the low fluid pressure valve adapted to initiate the material forming cycle when the material is partially pliable, a trigger mechanism arranged to continuously follow the movement of the forming tool during the forming cycle, and the electrical means actuated by trigger mechanism and adapted to operate the high fluid pressure valve so that pressure is applied to the activating means in response to the fully pliable condition of the material, and means responsive to the movement of said forming tool for exhausting the high pressure being applied to said tool.

2. In a thermal device for forming rigid material having a certain yield point at which the material becomes fully pliable the combination comprising, a low pneumatic pressure regulator means, a high pneumatic pressure means, a solenoid operated low pressure valve connected to the low pneumatic pressure regulator means, a solenoid operated high pressure valve connected to the high pneumatic pressure means and further connected to a line between the low pressure valve and the low pneumatic pressure regulator means, a check valve connected to the low pneumatic pressure regulator means, a pneumatic reservoir connected between the check valve and the high pressure valve, a forming tool means for shaping the material, means for supporting the material and for cooperating with the tool in shaping the material, thermal elements afl'ixed to the forming tool means for conditionmg the material to a pliable condition, means electrically activating the low pressure valve to initiate the actuation of the forming tool means into engagement with the material, a trigger mechanism continuously movable with the forming tool means when the material becomes partially pliable, adjusting means for regulating the movement limits of the trigger mechanism, means for electrically activating the high pressure valve in response to the trigger mechanism movement whereby the forming tool means completes the forming of the material when the material is fully pliable, means responsive to the movement of the forming tool means for electrically disconnectmg application of high pneumatic pressure from the forming tool, and an exhaust means for dissipating accumulated pneumatic pressure when the high pneumatic pressure -is disconnected from the forming tool means.

3. Apparatus for heat-forming a metal element comprising titanium or like materials, said apparatus comprising mutually opposed forming dies, means operatively associated with said dies for heating the metal element to be formed there/between to predetermined working temperature, means operable during such heating to apply pressure to the element between such dies with a force materially less than the force required for completing the forming operation, causing detectable initial deformation thereof when said temperature is reached, means adapted to detect such initial deformation, and means controlled by said latter means and operable in response to said detection to increase said force materially to a value effective to complete the forming operation.

4. Apparatus for thermally and physically shaping material having a certain yield point comprising a movable forming tool, a support vfor said material cooperating with said tool in shaping the material, heating elements associated with said tool for transmitting heat to said material, a pressure operated means moving said tool, a low pressure means and a high pressure means associated with said pressure operated means, said pressure operated means first activated by the low pressure means, a first means responsive to the movement of said tool for sensing the plasticity of said material, said first responsive means initiating the actuation of said high pressure means when said certain yield point is reached, said first responsive means connected to said pressure operated means, a second responsive means also connected to said pressure operated means, said second means responsive to the movement of said tool for sensing the final shape of said material and said second means exhausting the high pres sure from said pressure operated means.

5. Apparatus for thermally and physically shaping ma-' terial having a certain yield point as defined in claim 4 wherein said first responsive means has associated therewith an adjustable micrometer for manually controlling the point during the movement of said tool at which said material has attained its final shape.

6. A forming device for shaping a material having a certain yield point at which the material becomes'pliable comprising, a forming tool, a support for cooperating with said tool in shaping the material, heating elements associated with said tool, said forming tool having a shaft portion attached thereto, said shaft portion spring biased to retract said tool from said support, a cam member having an angular cam surface engaging the end portion of said shaft, said cam pivotally connected to said device, a piston positioned within a fluid operating chamber, said chamber being afiixed tosaid device, an extension arm integrallyc'onnected to said piston by one end thereof and having afiixed to the opposite end thereof a roller, said roller engageable with said cam and with a flat cam surface integrally alfixed to said device, said fluid operating chamber having connected thereto a first valve, said first valve having an exhaust port associated therewith, said valve controlled by a first solenoid, a fluid pressure system connected to said valve having a low pressure supply means and a high pressure supply means, a second valve disposed in said high pressure means for controlling the emission of high pressure fluid to said fluid operating chamber, a second solenoid operating said second valve, a plunger contacted at the loose end of said cam member, said plunger engageable with a first switch means, said first switch means operating said second solenoid foroperating said second valve to control said high pressure means, said extension arm having means afiixed thereto for operating a second switch means, said second switch means operating said first solenoid to operate said fluid valve for exhausting the fluid from said fluid operating chamber, through said exhaust port, and said first solenoid initially actuated by a tool in shaping said material, a fiuidoperating piston for moving said tool against said material a piston rod connected to said piston and having a forming, head connected to the free end thereof, said tool reciprocably mounted in said head and resiliently urged downwardly and restrained within said head, a switching means associat'ed with said device for increasing the fluid pressure operating said piston, said switch means comprising an adjustable set screw attached to said forming head and a mechanically actuated electrical switch means connected to said support means, said set screw actuating said switching means as said tool and said forming head re forced'downwardly toward said support, the point of said .movement at which said switching means is autuated being accurately adjustable by means of said set screw.

465,089 Ries Dec. 15, 1891 1,174,446 'Rietzel Mar. 7, 1916 1,261,943 Lashar Apr. 9, 1918 1,295,048 Macdonald Feb. 18, 1919 1,848,271 Phelps Mar. 8, 1932 1,951,426 Littler Mar.'20, 1934 2,331,537 Clark Oct. 12, 1943 2,395,849 Collom et al Mar. 5, 1946 2,405,033 Grimes July 30, 1946 2,407 ,314 Mason Sept. 10, 1946 2,449,247 Paucek Sept. 14, 1948 2,459,047 Scharf Jan. 11,, 1949 2,460,519 Marchant Feb. 1, 1949 2,592,672 Fischer 2. Apr. 15, 1952 2,737,224 Jones Mar, 6, 1956 2,743,933 7 Baines May l, 1956. 2,852,060 r Gunther Sept. 16, 1958 OTHER REFERENCES Metal Industry-The disclosure on page 213 for Sept. 13, 1946. 

1. A FORMING DEVICE FOR SHAPING A MATERIAL HAVING A CERTAIN YIELD POINT AT WHICH THE MATERIAL BECOMES FULLY PLIABLE COMPRISING, THE COMBINATION OF A BASE ASSEMBLY, A FORMING TOOL MOVABLE ON THE BASE ASSEMBLY, MEANS CARRIED ON THE BASE ASSEMBLY FOR SUPPORTING THE MATERIAL AND FOR COOPERATING WITH THE TOOL IN SHAPING THE MATERIAL, HEATING ELEMENT AFFIXED TO THE FORMING TOOL IN THERMAL RELATIONSHIP TO THE MATERIAL FOR MAKING THE MATERIAL PLIABLE ACTIVATING MEANS CARRIED BY THE BASE ASSEMBLY FOR MOVING THE FORMING TOOL, A FLUID PRESSURE SYSTEM CONNECTED TO THE ACTIVATING MEANS COMPRISING A LOW FLUID PRESSURE VALVE AND A HIGH FLUID PRESSURE VALVE, THE LOW FLUID PRESSURE VALVE ADAPTED TO INITIATE THE MATERIAL FORMING CYCLE WHEN THE MATERIAL IS PARTIALLY PLIABLE, A TRIGGER MECHANISM ARRANGED TO CONTINUOUSLY FOLLOW THE MOVEMENT OF THE FORMING TOOL DURING THE FORMING CYCLE, AND THE ELECTRICAL MEANS ACTUATED BY TRIGGER MECHANISM AND ADAPTED TO OPERATE THE HIGH FLUID PRESSURE VALVE SO THAT PRESSURE IS APPLIED TO THE ACTIVATING MEANS IN RESPONSE TO THE FULLY PLIABLE CONDITION OF THE MATERIAL, AND MEANS RESPONSIVE TO THE MOVEMENT OF SAID FORMING TOOL FOR EXHAUSTING THE HIGH PRESSURE BEING APPLIED TO SAID TOOL. 